At the northwest corner of Central Park, construction is under way on Frederick Douglass Circle, a $15.5 million project honoring the escaped slave who became a world-renowned orator and abolitionist.

Beneath an eight-foot-tall sculpture of Douglass, the plans call for a huge quilt in granite, an array of squares, a symbol in each, supposedly part of a secret code sewn into family quilts and used along the Underground Railroad to aid slaves. Two plaques would explain this.

The only problem: According to many prominent historians, the secret code —the subject of a popular book that has been featured on no less a cultural touchstone than “The Oprah Winfrey Show” — never existed

Relying on the oral history of one family without corroboration from other sources is what offends historians like Giles Wright, an Underground Railroad expert who works for the New Jersey Historical Commission. "The Underground Railroad is so rife with distortions and misinformation, and this is just one more instance when someone comes across folklore and assumes it's true," he says.